OLED Reflection Layer Rugged Surface Light Extraction
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Solution Overview
Problem
Conventional OLED devices face issues with luminance enhancement, negative battery effects, corrosion, and film delamination due to rugged top surfaces and the need for additional processes in forming planar layers, which hinder light extraction efficiency and reliability.
Innovation Solution
An image display device is fabricated with a substrate having a luminance region and a non-luminance region, featuring an interlayer dielectric layer, a reflection layer with a rugged top surface, a planarization layer, and sequentially stacked electroluminescent layers, which improves light coupling and extraction efficiency while reducing negative effects and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the planar insulating layer is formed with a rugged top surface to improve light extraction efficiency, then luminance is improved, but film delamination occurs between the anode and the planar insulating layer
Solution Approach 1:
The patent introduces a buffer layer as an intermediary between the anode and the planar insulating layer with rugged top surface. This buffer layer mediates the interface between the two layers, preventing direct contact and thus preventing film delamination while still allowing the rugged surface to enhance light extraction efficiency and luminance.
Solution Approach 2:
The buffer layer is formed in advance before the planar insulating layer with rugged top surface. This beforehand cushioning provides protective support at the interface, preventing the harmful effect of film delamination before it can occur, while maintaining the beneficial light extraction properties.
2Illumination intensity
If the anode functions as a reflection layer to improve light extraction, then luminance is improved, but negative battery effects and corrosion occur at edges of the anode
Solution Approach 1:
The buffer layer acts as an intermediary between the anode/reflection layer and the planar insulating layer. It provides electrical insulation and physical separation, preventing the harmful battery effects and corrosion that would otherwise occur at the edges of the anode while maintaining the light reflection function.
Solution Approach 2:
The patent separates the reflection function from the anode by introducing the buffer layer. The anode can focus on its primary function of charge injection while the buffer layer provides the insulating barrier that prevents harmful side effects, effectively extracting the problematic functions from the anode structure.
3Ease of manufacture
If a planar layer is added over the reflection layer to facilitate element fabrication, then manufacturing ease is improved, but the light emitting area becomes smaller, hindering light extraction efficiency
Solution Approach 1:
The planar insulating layer with rugged top surface is applied locally only in the luminance region where light extraction is needed, rather than uniformly across the entire device. This allows the rugged surface to enhance light extraction efficiency in the light emitting area while still providing fabrication convenience where applied.
Solution Approach 2:
Instead of adding a separate planar layer that would reduce the light emitting area, the patent creates a rugged top surface dimension on the planar insulating layer itself. This dimensional change on the surface level provides both the planarization needed for fabrication and the light extraction enhancement without sacrificing light emitting area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances image resolution and lifetime by improving light extraction efficiency, reducing negative battery effects and corrosion, and simplifying the fabrication process, leading to a more reliable OLED device with improved luminance and viewing angle.
Implementation Method 1
a reflection layer is disposed over the interlayer dielectric layer in the luminance region
Implementation Method 2
having a rugged top surface corresponding to the reflection layer
Implementation Method 3
An electroluminescent layer and a second electrode are sequentially stacked over the first electrode
Data Source
AI summary
A display device including a display panel is provided, including a substrate having a luminance region and a none-luminance region thereover. An interlayer dielectric layer is disposed over the substrate. A reflection layer is disposed over the interlayer dielectric layer in the luminance region. A planarization layer is disposed over the reflection layer, having a rugged top surface corresponding to the reflection layer. A first electrode is disposed over the planarization layer, having a rugged top surface corresponding to the reflection layer. A pixel defining layer is disposed over the planarization layer, exposing the rugged top surface of the first electrode and defining the luminance region. An electroluminescent layer and a second electrode are sequentially stacked over the first electrode.